1. Field of the Invention
The present invention relates to transmitting and receiving communication signals, and more particularly, to a transceiving apparatus and related transceiving system that can generate a common mode voltage of its receiver module by referring to the common-mode voltage of its transmitter module when the transceiving apparatus operates in the RX mode.
2. Description of the Prior Art
DisplayPort, a new interface standard from the Video Electronic Standards Association (VESA), simplifies display design and its associated connections. It also supports higher resolutions with robust electrical characteristics. Although the immediate application of the DisplayPort interface is in notebooks and display monitors, it is also designed to be robust for many embedded and internal applications, such as digital TVs.
Each transceiving apparatus applied to the DisplayPort consists of a receiver and a transmitter. In accordance with the DisplayPort specification, a turn-around voltage, which is defined as a voltage difference between the common mode voltage of the transmitter and the common mode voltage of the receiver, must be smaller than 0.4 V, regardless of the source side or sink side. Those skilled in the art should readily appreciate that it is very difficult to maintain the common mode voltage. For example, if the amplitude of the transmitter is changed, its common mode voltage will change accordingly. In addition, the total impedance should be maintained in 50 ohms. Also, there are AC coupling capacitors each having a capacitance of 100 nF and disposed between two transceiving apparatuses, such as a source side and a sink side, connected to each other. If the transceiving apparatus is switched from a transmitter mode (TX mode) to a receiver mode (RX mode), it may waste much time to transfer the common voltage of the transmitter included therein into the common voltage of the receiver included therein.
Hence, how to solve the abovementioned issues has become an important topic of designing the transceiving apparatus.